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Compendium
September 2024
Volume 45, Issue 8
Peer-Reviewed

Digital Platform Facilitates Successful Facially Driven Orthodontic–Restorative Treatment

Ryan Tak On Tse, BDS, MClinDent, MSc

Abstract: This case report presents a novel digital technique for prosthetically driven orthodontic treatment. A 28-year-old patient who had undergone orthodontics as a teenager experienced a relapse and presented with esthetic concerns. The author utilized state-of-the-art software to create a virtual orthodontic-restorative treatment outcome with virtual restorations. This approach helped guide tooth movement, improve team communication, and optimize treatment outcomes while allowing for minimally invasive restorative treatment.

Prerestorative orthodontic treatment offers numerous advantages, including the opportunity to optimize esthetics, enhance biological and functional outcomes, and preserve tooth structure. Executing an interdisciplinary approach, however, can be challenging if communication among restorative dentists, orthodontists, and patients is lacking. Restorative dentists may overlook the benefits of orthodontic tooth movement, patients may be unwilling to undergo orthodontic treatment because of a lack of understanding and appreciation for its value,1 and orthodontists may be unfamiliar with the restorative concepts that need to be integrated into the treatment plan.

In recent years digital orthodontics using clear aligner systems have provided effective control over tooth movement while supporting smile design and treatment plans.2-4 This approach can increase patient acceptance and facilitate minimally invasive dentistry.

This case report highlights the use of one such digital treatment planning platform, Invisalign® Smile Architect™ (Align Technology, Inc., invisalign.com). This facially driven orthodontic-restorative treatment planning platform provides a single ecosystem for combined visual treatment planning of orthodontics and restorations. The software allows for assessing the need for tooth movement, moving teeth within the prosthetic envelope in three dimensions, facilitating team communication, helping patients understand the value of prosthetic-driven digital orthodontics, and achieving minimally invasive restorative treatment.

Case Presentation

A 28-year-old female patient presented with concerns about the esthetics of her proclined maxillary incisors and a gingival embrasure (ie, black triangle) between teeth Nos. 8 and 9 (Figure 1). She had undergone orthodontic treatment as a teenager, but relapse had occurred. Her chief complaint was an unpleasing smile. She desired a treatment plan that could be completed relatively quickly while preserving as much tooth structure as possible. She wanted any orthodontics to be short-term.

Upon intraoral examination, the clinician observed that the patient had an anterior open bite from teeth Nos. 7 through 10, a shifted and tilted dental midline to the right, and mesially tilted teeth Nos. 8 and 9 with a black triangle. Also, tooth No. 8 appeared darker than tooth No. 9 (Figure 2). Tooth No. 8 was nonvital, but no periapical pathology was found.

Patient documentation included standard photographs, a standard tessellation (STL) file generated from an intraoral scan (iTero™ Element 5D Plus, Align Technology, Inc, itero.com), and a full panoramic and lateral cephalogram radiographs for case assessment.

Treatment Plan

The treatment plan began with a facially driven assessment,5,6focusing on the position of the incisal edges of the maxillary incisors,7,8 tooth proportion, smile curve, and gingival architecture (Figure 3). The treatment plan involved short-term orthodontics to correct the anterior open bite by retracting and extruding teeth Nos. 7 through 11 using clear aligners. This approach would offer esthetic and stable results but would not address the black triangle between the central incisors or the tooth proportion between the central and lateral incisors.

Veneers were planned for teeth Nos. 8 and 9 to modify tooth size and close the black triangle, thus further enhancing the
esthetic outcome.9,10 During the aligner treatment, a bleaching gel (Opalescence™, Ultradent, ultradent.com) would be prescribed
to be used in the aligner to whiten tooth No. 8 for 4 weeks.

Virtual Treatment Outcome

A virtual treatment outcome was generated by submitting three standard photographs (frontal view, frontal view with smile, and lateral view with smile) taken using the Invisalign Practice App and the intraoral scan's STL file to the Invisalign system (ie, Invisalign Doctor Site). The clinician chose "Smile Architect" on the Invisalign site, and an orthodontic + restorative Clincheck® simulation was generated with in-face visualization (Figure 4). The clinician was able to add or remove restorations according to the treatment plan and also modify the shape, length, and size of the restorations.

With the ideal tooth position determined, an optimal force system was designed to move the teeth precisely to their intended positions. The integration of the orthodontic and restorative interface enhanced the execution of the treatment plan.

Treatment Phase

Prosthetically driven tooth movement was achieved using 3D control of tooth movement in the Smile Architect platform. The clinician can control the tooth movement within the prosthetic envelope. The gingival margin was aligned, while the incisal edge was left with 1 mm of space, lessening the need for incisal edge reduction for veneer preparation (Figure 5). This approach also minimized the required tooth movement and number of aligners. Additionally, teeth Nos. 7 and 8 could be retracted palatally to create space for future veneers (Figure 6). Fourteen aligners, changed every 1 week, were used to correct the anterior open bite (Figure 7). Total orthodontic treatment time was 14 weeks.

Using prosthetically driven digital orthodontics, the teeth were positioned ideally for conservative prosthetic preparations, preserving as much tooth structure as possible. This allowed for minimal incisal edge reduction and labial reduction (Figure 8). The gingival margin was repositioned according to the smile design, eliminating the need for crown lengthening surgery. The clinician performed a mock-up using the STL file in the platform and prepared teeth Nos. 7 and 8 accordingly.

Tooth preparation entailed preparing veneers for teeth Nos. 8 and 9 based on the mock-up. Tooth No. 8 was lightened but still retained its internal discoloration. Theoretically, No. 8 would need to be prepared slightly deeper than usual in order to provide adequate space for the ceramist to mask the darkened dummy shade. The clinician, however, chose to prepare it the same as No. 9 to preserve more enamel and allow the ceramist to mask the darkened dummy shade with ceramic (Figure 9). Temporary veneers (Luxatemp, DMG America, dmg-america.com) were bonded to restore the patient's smile and confirm the final appearance.

Clinical photographs were taken according to guidelines from the ceramist to provide him information for shade matching (Figure 10 through Figure 12). An intraoral scan with the STL file was taken and sent to the ceramist for the fabrication of the lithium-disilicate veneers (IPS e.max®, Ivoclar, ivoclar.com) (Figure 13 and Figure 14). The veneers were cemented with a luting composite (Variolink Esthetic, Ivoclar). The patient was followed-up at 1 week, 1 month, and 3 months post-treatment (Figure 15 through Figure 17).

Discussion

This case report highlights the advantages of using a prosthetically driven digital orthodontic treatment planning platform (Smile Architect) to achieve an optimal treatment outcome. By integrating orthodontic and restorative concepts, the software allows for precise tooth movement within the prosthetic envelope, helping to preserve tooth structure and reduce the need for invasive procedures. The virtual treatment outcome and in-face visualization help facilitate effective communication among the dental team and enhance patient understanding and acceptance of the treatment plan.

The presented case demonstrated the successful correction of an anterior open bite, alignment of the gingival margin, closure of a gingival embrasure, and enhancement of tooth proportion using a combination of short-term orthodontics and veneer restorations. The digital platform allowed for the generation of a virtual treatment plan that both guided the tooth movement and expedited the restorative procedures. The result was an improved esthetic outcome, patient satisfaction, and minimal tooth structure removal.

Conclusion

This novel digital technique, which utilizes an innovative 3D software design, offers promising possibilities for prosthetically driven orthodontic treatment. It provides a comprehensive and interdisciplinary approach to achieving optimal esthetic and functional results. In the present case it was used to minimize incisal edge reduction and labial reduction, reposition the gingival margin according to the smile design, and lessen the need for surgical intervention. The integrated orthodontic-restorative treatment planning platform allows the clinician to plan orthodontic and restorative treatment simultaneously. Alternatively, the restorative dentist and orthodontist can plan the case together, saving treatment time and helping increase predictability.

Acknowledgment

The author thanks ceramist Naoki Hayashi, RDT, MDT, MDC, and the team at Ultimate Styles Dental Laboratory (ultimate-dl.com) for the fabrication of the veneers in this case.

Disclosure

The author had no disclosures to report.

About the Author

Ryan Tak On Tse, BDS, MClinDent(London), MSc(ImplantDent)(HK)
Honorary Assistant Professor, Faculty of Dentistry, University of Hong Kong; Private Practice, Hong Kong; Membership, Faculty of General Dental Practitioners (UK); Membership, General Dentistry (MGD)

References

1. Boyd RL. Esthetic orthodontic treatment using the invisalign appliance for moderate to complex malocclusions. J Dent Educ.2008;72(8):948-967.

2. Rossini G, Parrini S, Castroflorio T, et al. Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review. Angle Orthod. 2015;85(5):881-889.

3. Weir T. Clear aligners in orthodontic treatment. Aust Dent J.2017;62 suppl 1:58-62.

4. Tse RT. Merging clear aligner therapy with digital smile design to maximize esthetics and minimize tooth reduction. Compend Contin Educ Dent.2019;40(2):100-106.

5. Spear F. The maxillary central incisor edge: a key to esthetic and functional treatment planning. Compend Contin Educ Dent.1999;20(6):512-516.

6. Kois JC. Diagnostically driven interdisciplinary treatment planning. Seattle Study Club J. 2002;6(4):28-34.

7. Small BW. Location of incisal edge position for esthetic restorative dentistry. Gen Dent. 2000;48(4):396-397.

8. Sarver DM. The importance of incisor positioning in the esthetic smile: the smile arc. Am J Orthod Dentofacial Orthop. 2001;120(2):
98-111.

9. Chiche G, Cohen M. Proportion, display, and length for successful esthetic planning. In: Cohen M, ed. Interdisciplinary Treatment Planning: Principles, Design, Implementation. 1st ed. Quintessence Publishing; 2008:21-29.

10. Sarver DM. Principles of cosmetic dentistry in orthodontics: Part 1. Shape and proportionality of anterior teeth. Am J Orthod Dentofacial Orthop. 2004;126(6):749-753.

Fig 1. Pretreatment full-face smile. The patient’s proclined maxillary incisors and the presence of a black triangle impacted her smile.

Figure 1

Fig 2. Intraoral examination revealed an anterior open bite with teeth Nos. 8 and 9 tilted mesially, which further affected the smile and brought attention to the black triangle. Tooth No. 8 appeared discolored.

Figure 2

Fig 3. Using digital smile design, the clinician determined the ideal position of the incisal edges of the maxillary incisors based on facial esthetics. This information was then used to communicate the treatment goals to the patient.

Figure 3

Fig 4. The software interface incorporated a smile design framework into the patient’s smile photograph alongside a ClinCheck image. The smile design framework assists the clinician in determining such factors as the midline, smile curve, and size and shape of the restorations. The technician can design attachments to facilitate tooth movement and guide the teeth toward the desired treatment goals.

Figure 4

Fig 5. The clinician opted for two veneers on teeth Nos. 8 and 9. The software generated a virtual representation of the treatment outcome (in-face visualization), which was valuable in communicating with the patient and inspiring her to proceed with the treatment.

Figure 5

Fig 6. Utilizing 3D controls, the clinician was able to manipulate the position of teeth Nos. 8 and 9 within the prosthetic envelope (the planned veneer area). The clinician intends to align the gingival margins of both teeth. Additionally, the incisal edge of the central incisors will be set 1 mm shorter than the veneers, minimizing the need for incisal reduction and eliminating the need for crown lengthening.

Figure 6

Fig 7. Post–orthodontic treatment, after 14 sets of aligners. Tooth alignment was well in accordance with the ClinCheck plan. The angulation of teeth Nos. 8 and 9 was corrected.

Figure 7

Fig 8. Two larger veneers were planned as part of the smile restoration. The clinician can export the STL file from the software for the mock-up and tooth preparation.

Figure 8

Fig 9. Veneer preparation for teeth Nos. 8 and 9 with minimal reduction and a 0.3-mm chamfer. The interproximal area needed to be opened to provide space for the ceramist to address the black triangle. Tooth No. 8 was darker than No. 9, but the clinician did not prepare it deeper so that the ceramist could mask the dark color.

Figure 9

Fig 10 and Fig 11. A series of photographs was taken with a shade guide attached to the gingival tab. Photographs were taken of the maxillary (Fig 10) and mandibular (Fig 11) incisors.

Figure 10

Fig 10 and Fig 11. A series of photographs was taken with a shade guide attached to the gingival tab. Photographs were taken of the maxillary (Fig 10) and mandibular (Fig 11) incisors.

Figure 11

Fig 12. A “dummy” shade was taken using a shade tab made of natural die material. Tooth No. 8 is shade ND2, and tooth No. 9 is shade ND1. There was an obvious shade difference between the two central incisors

Figure 12

Fig 13. The ultra-thin lithium-disilicate veneers were fabricated by the ceramist.

Figure 13

Fig 14. Veneer No. 9 was intentionally made slightly darker than No. 8 to compensate for the color difference between the two central incisors. This approach was taken instead of using opaque porcelain to mask the darker shade of No. 8.

Figure 14

Fig 15. Retracted view 3 months after cementation of the veneers. By this time the veneers had naturally harmonized with the adjacent teeth.

Figure 15

Fig 16. Photograph of the veneers 3 months post-treatment with black background, showcasing the ideal shade-matching of Nos. 8 and 9 and the excellent craftsmanship of the ceramist.

Figure 16

Fig 17. Three-month post-treatment portrait photograph of the patient, who was satisfied with the harmonious appearance of the veneers. She also appreciated the prerestorative aligner therapy, which helped enhance the final result while preserving natural tooth structure.

Figure 17

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